System of electric-motor control.



F. n. HALLOCK. SYSTEM OF ELECTRIC MOTOR CONTROL.

APPLICATION HLED AU,G. I2, 1912;

Patentd July 6,1915.

Fla 2.

INVENTOR ATTORNEY 1 UNITED STATES PATENT or ioE.

FLETCHER D. HALLOCK, OF PITTSBURGH,-PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A. CORPORATION 0F PENN- SYLVANIA.

SYSTEM OF ELECTRIC-MOTOR CONTROL.

Specification of Letters Patent.

Application filed August 12, 1912. Serial No. 714,504.

To all whom it may concern Be it known that I, FLETCHER D. HAL- LOCK, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a. new and useful Improvement in Systems of Electric-Motor Control, of'which the following is a specification.

My invention relates to systems of con trol for electric motors and it has special reference to such systems as are adapted to govern the operation .of electric motors during periods of starting or acceleration.

One "of the objects of my invention is to provide a system of the above-indicated character which shall be simple in arrange preventing connection of the motor on the a line without the proper amount of resistance in circuit. Furthermore, I associate with the switching device, hereinbefore mentioned, suitable means for effecting the interruption of the supply of energy to the motor in case theswitching device is left in an intermediate position, or in case it is moved out of its full closed position after having been fully closed.

By reason of my invention, the motor is protected against excessive operating and starting conditions and may be operated without difficulty by a moderately skilled or unskilled attendant.

My invention may best be understood by .reference to the accompanying drawing in Figure 1 is a diagrammatic view of a system of control embodying my invention, and Fig. 2 is a similar view embodying a modification thereof.

\ Referring to Fig. 1, a supply circuit 12 is adapted to deliver energy toan electric motor 3, having an armature 4: anda field magnet winding 5, through a line switch 6, an electrically operated main switch 7, an overload relay 8, a starting resistor 9 and a switching device 10, adapted to govern the circuit connections of said starting resistor.

The motor 3, the line switch 6, the elec-- trically operated switch 7 and the overload relay 8 may be of any well known construc-' tion and no detailed description of these devices is deemed necessary, inasmuch as the construction and the operation of such devices is old and familiar to those skilled in the art. Since these devices are shown for illustrative purposes, any other suitable devices for accomplishing the same results may be employed.

The switching device 10 preferably comprises a pivotally-mounted switch member or blade 11 that is provided with a handle 12 and is adapted to. successively and cooperatively engage a plurality of stationary cont-act members 13, said members being Patented July 6, 1915.

electrically connected to the starting resistor 9 at intermediate points by means of conductors 14.

I do not wish to be restricted to the particular form of starting device shown and described because various other forms may be equally well employed.

An auxiliary switch 15, having stationary contact terminals 16 and a bridging switch member 17, is biased to its open position by means of a weight 18, or other means, and

1S mechanically associated with the switch member 11, when it occupies its full open position. by means of a suitable pivotally mounted bell-crank lever 19 and a supporting stem 20. The arrangement of parts is such that the auxiliary switch 15 is maintained in a closed position only whenthe switch member 11 is in its full open position and rests against a suitable stop 21.

An auxiliary switch 22, having stationary contact terminals 23 and a bridging member 24:, is normally biased to its open position by a weight 25 and is mechanically associated with a pivotally mounted lever member 26 having a handle 27. By means of the handle 27, the switch 22 may be manually held in its closed position during the start- .ing operation and may be, restrained, in said handle 12 of the switch member 11 when said switch member occupies its full closed position.

Evidently, switches 15 and 22 and the mechanisms by means of which theoperation of said switches is rendered dependent upon the position of the switch member 11, form no material parts of my present invention, and any suitable devices for efiecting the same results in substantially the same manner may be employed in lieu thereof. 7

Assuming the arrangement of parts and the circuit connections to be as shown in the figure, the operation of the system is as follows: In order to start the motor 3, the line switch 6 is closed, after which the auxiliary switch 22 ismanually closed by the operator and held in this position during the complete starting operation. As'soon as the switch 22 is closed, energy is supplied to a closing coil of the electrically operated switch 7 from the supply circuit conductor 1, through conductor 31, line switch 6, conductor 32, cooperating switch members 23 and 24 of auxiliary switch 22, conductor 33, conductor 34, cotiperating switch members 16 and 17' of auxiliary switch 15, conductor 35, conductor 36, coeperating switch members 37 and 38 of the overload rela-y-8, conductor 39, closing coil 30, conductor 40, line switch 6 and conductor 41 to the supply circuit conductor 2. Upon the completion of the circuit just recited, a movable core member 42 of the electrically operated switch 7 becomes energized and the cooperative engagement of a movable switch member 43 and stationary contact terminals 44 of said switch is effected. Thus, a circuit-is established from the supply circuit conductor 1, through conductor 31, line switch 6, conductor 46', cooperating switch members 43 and 44 of the electrically operated switch 7, conductor 47, energizing coil 48 of the overload relay 8, conductor 49, all of the sections 50 of the starting resistor 9, conductor 51, motor 3, conductor 52, line switch 6 and conductor 41 to the supply circuit conductor 2. Having established the circuits just described, energy is supplied to the motor 3 through all of the sections of resistor 9 and said motor is caused to start.

contact members 13, thereby short-circuiting and eliminating from. clrcuit the several sections 50 of the starting resistor 9 step-bystep. It will, of course, be understood that, as the resistor 9 is gradually short-circuited,

the energy supplied tothe motor 3 and, con-v sequently,'- the speed thereof will be ,increased.

In case the operator attempts to close the the structural details of the I starting switch 10 at a speed in excessof a predetermined rate,the current in the motor circuit increases to such a value that the overload relay 8 is energized and effects a separation of its coeperating contact members37 and 38. Thus, an interruption in the control circuit of the closing coil 30 of electrically operated switch 7 is effected, and

.said switch is allowed t'o open, thereby interrupting the supply of energy to the motor 3. It is obvious, therefore, that the motor 3 cannot be subjected to excessive starting currents by reason of carelessness of the operator or the improper operation of the ductor 36, is interrupted. However, when the electrically operated switch 7 closes, its

cotiperating switch members 53 and 54 are closed, thereby establishing a shunt circuit from the conductor 33, through conductor 55', coeperating switch members 53 and 54 of the electrically operated switch 7, and conductor 56 to the, conductor 36. Hence, when the auxiliary switch 15 opens, the control circuit of the electrically operated switch 7 is still -maintained through the switch members 53 and 54 associated therewith.

For a further understanding of the operation of the system, let it be. assumed that the starting switch 10 occupies an intermediate position and that the action of the overload relay 8, in response to an excessive current, has effected the opening of the electrically operated switch 7. Under these conditions, it will be seen that, although the auxiliary switch 22 may be held closed, noenergy is delivered to the closing coil 30 of the switch 7 by reason of the fact that the auxiliary switch 15 is open as well as the coeperating contact members 53 and 54 which are associated with the switch 7. y

In order to again start the motor 3, it is, therefore, necessary to move the switch member 11 of the starting switch 10 back to its full open or ofi position against the I stop 21, whereby the auxiliary switch 15 is again closed by reason of the mechanical connection between the member 11 and the switch 15 hereinbefore described. Having returned the switch member 11 to its 01f position, the starting operation may then be carried out in the manner already set forth.

After having fully closed the starting closed position, after which the motor 3 may .be allowed to operate without further attention.

By reasonof the peculiar arrangement of the auxiliary switch 22- with respect to the starting switch 10, it is manifest that an interruption of the supply of energy to the motor-.3 is effected in case the operator should release the auxiliary switch 22 and attempt to leave the switching devices 10 in an intermediate position, for the reason that an interruption of the control circuit to the 'closing coil 30 of electrically operated switch would immediately be effected. It is impossible, therefore, to operate the motor 3 withany of thestarting resistor 9 in circuit therewith except during thestarting operation when the operator manually holds the auxiliary switch 22 closed.

Assuming the motor 3 to be operating at full running speed and the switch 10 to occupy its full closed position, it is evident that an interruption of the supply of energy to the motor 3 will be effected if the movable member 11 of the starting switch 10 is moved out of its full closed position. -An

interruption of the supply of energy to the motor 3 is also eflected in the event of a condition of no-voltage' obtaining on the system, inasmuch as such a condition would deenergize the closing coil 30 of the electri-' .tions of starting resistor'9 Each portion of starting resistor 9 iselectrically connected to a plurality of stationary contactmembers 13 which are adapted to be cooperatively engaged by a pivotally mounted switch member 11 Tl18 several movable switch members 11 "are mechanically and rigidly associatedby means of a cross bar 61 of insulating material having a handle 12 associated therewith. The rigidly connected switch members 11 and the cooperating stationary contact terminals 13 constitute a' three pole starting switch 10,

Qwhich corresponds to the starting switch 10 described inconnection with Fig. 1. A plurality of auxiliary switches 22 and 15 arealso associated with the starting switch 10".

5.4 relay 8 is connected in circuit with the conin a manner similarto that hereinbefore set forth.

The motor 3) receives energy from a polyphase source 62, 63 and 64, through a plu- "rality of conductors 65, 66 and 67, an electrically operated switch 7 and a plurality of conductors 68, G9 and 70. The electrically operated switch 7 comprises a plurality of'stationary contact member M and movable cooperating contact members 43 and is also provided with the closing coil 30, a magnetizable core 42 and with auxiliary cooperating contact members 53 and An energizing coil et8 of an overload ductor 68 and is, therefore, responsive in its action to the amountof current traversingsaid conductor.

as follows, no detailed description thereof being given for the reason that it is believed that those skilled in the art will experience no difliculty in understanding the operation and in tracing the circuits thereof by reason of their similarity to the operation and circuit connections hereinbefore fully described with respect to Fig. l: The auxiliary switch 22 is first closed manually,- thereby energizing the closing coil 30 and effecting the closure of the electrically operated switch 7 Thus, energy is supplied -to the primary winding 58 of the motor 3 and said motor is started from rest. The closure of the electrically operated switch 7 also effects the closure of the auxiliary contact members 53 and 54?, thereby estab- I lishing a multiple circuit around the auxiliary switch 15 to insure the energization of the closing coil 30 subsequent to the operation of the starting switch 10*. In order to bring the motor 3 up to speed, the starting switch 10 is gradually closed upon its stationary contact members 18*, whereby the several sections of starting resistor 9 are eliminated step-by-step from the secondary circuit of the motor 3 until said starting switch 10 is fully closed, thereby mechanically restraining the auxiliary switch 22 in its closed position. i

Although I have shown and described systems of control embodying specific arrangements of apparatus and circuit connections, I do not wish to be restricted in this respect, as many modifications may be effected without departing from the spirit and scope of my invention, and I desire that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. In a control system, the combination with a motor, a starting resistor. a shortcircuiting switching device therefor and an electrically operated nee switch, of an auxiliary switch held in the energizing circuit of saidelectrically operated switch when said short-circuiting switch is in its off position, and a second-auxiliary switch inseries circuit therewith and manually held closed during the short-circuiting operation.

2. In a control system, the combination with a supply circuit, an electric motor, a starting resistor therefor, and switching means for gradually short-circuiting said resistor, of manually restrained means for interrupting the supply of energy to said motor if released during the starting operation, said means being mechanically restrained during normal operation of the motor, and means in series circuit with said lastnamed means for preventing further operation of the system until said switching means is returned to its off position.

3. In a control system, the combination with a supply circuit, an electric motor, a starting resistor therefor and switching means for gradually short-circuiting said resistor, an electrically operated switch in circuit with said motor, of means manually restrained during starting and mechanically restrained thereafter for interrupting the supply of energy to said electrically operated switch if released during the starting operation controlling the supply of energy to said switch, means for preventing further operation of the system until said switching means is returned to its off position, and eleetro-responsive means for interrupting the supply of energy to said switch if said switching means is operated in excess of a predetermined speed.

4:. In a control system, the combination with a supply circuit, an electric motor, a

starting resistor therefor, a switching device for short-circuiting said resistor step by step, and a main switch in circuit with said'motor, of an auxiliary switch for controlling the operation of said main switch, said auxiliary switch-being biased to one of its positions and adapted to be manually restrained in its other position during the starting operation and mechanically restrained in said position by said switching device when said device is fully closed.

5. In a control system, the combination with a supply circuit, a translating device and a -manually operated starting device therefor, of automatic means for interrupting the supply of energy when said starting device is operated in excess of a predetermined speed, manually restrained means for interrupting the supply of energy when released during the starting operation, and means for preventing further operation of said system until said starting device is returned to its ofli' position.

6. In a control system, the combination with a supply circuit, a translating device, a starting device therefor, and an electrically operated switch in circuit with said translating device, of a plurality of auxiliary switches in the control circuit of said electrically operated switch, said auxiliary switches being respectively mechanically associated with said starting device when it occupies its full open and its full closed position, whereby the operation of said electrically operated switch is rendered dependent upon the position of said starting device.

7. In a control system, the combination with a supply circuit, a translating device, a manually operated switching device therefor, and an electrically actuated switch in circuit with said translating device,of a plurality of auxiliary switches in the control circuit of said electrically operated switch and mechanically dependent upon the operation of said starting device for controlling the operation of said electrically operated switch.

8. In a control system, the combination with a supply circuit, an electric motor, a starting resistor therefor, a switching device for short-circuiting said' resistor step by step, and an electrically operated switch in circuit with said motor, of electro-responsive means for interrupting the control circuit of said electrically operated switch under predetermined circuit conditions, an auxiliary switch in said control circuit and adapted to be held closed by said switching device only when it occupies its full open position, and a second auxiliary switch in said control circuit normally biased to its open position and adapted to be manually held in its closed position during the starting operation of said motor and to be restrained in said position by said switching device when said switching device occupies its full closed position.

9. In a controlsystem, the combination with a supply circuit, an electric motor, a starting resistor, a switching device for short-circuiting said resistor and an electrically operated switch in circuit with said motor, of a plurality of auxiliary switches initially in series circuit relation and adaptloo ed to deliver energy for operating said FLETCHER D. HALLOCK. WVitnesses Tnnononn VARNEY,

B. B. HrNEs.

Corrections in Letters Patent No.1 ,1 45,680.

It is hereby certified that in Letters Patent No. 1,145,680,grai1tecl July 6, 1915, upon the application of Fletcher D; Hollock, of Pittsburgh; hennsyiiraniag I for an improvement in Systems ofElectric-Motor Control, errors-ieppear in the printed specification requiring correction as follows: Page 4 line 29, after the Word operation? insert the word means; same page, line 30, strike out the ord means and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the ,case in the Patent Office.

Signed and sealed this 10th day of August, A. 1)., 1915.

' v R. WIHTEHEAD,

Acting Commissioner .of Pcz'enfi [SEAL] It is hereby certified that in Letters Patent No. 1,145,680, granted July 6, 1915, upon the application of Fletcher D; Hallock, of Pittsburgh, jPennsyii/ania;

for an improvement in Systems of Electric-Motor Control, errorsnpioear in the printed specification requiring correction follows: Page 1, line 29, after the word operation insert the Word means; samepage, line 30, strike out the Word means and that the said Letters Patent should be read with these corrections therein that we same may conform to the record of the ,case in the Patent Office.

' Signed and sealed this 10th day of August, A. 1)., 1915.

i n. 1 WHITEHEAD,

Acting Commissioner of Patents.

[SEAL] 

